Eschatology is a very big and fancy word that means the study of what will happen at the end of the world. People who believe in Jehovah's Witnesses have a unique way of thinking about the end of the world. Let's break it down in a way that is easy for a 5 year old to understand.
Jehovah's Witnesses believe that God made the world, and that one day he will bring it to an end. They think that the end will be a scary and bad time, but also that it will be a time for good things to happen.
They think that when the end of the world comes, God will send Jesus to Earth. Jesus will come as a king, and with him, he will bring all of the people who have ever died back to life. Jehovah's Witnesses call this the "resurrection."
At this point, there will be two groups of people: those who believe in God and those who do not. They think that God will only save the people who believe in him and that all of the people who do not believe will be punished.
Those who are saved will live in a new world that God will create. Jehovah's Witnesses call this the "paradise earth." This new world will be free of sickness, death, and suffering. People will live forever and be happy with their families and friends.
To sum up, Jehovah's Witnesses believe that the end of the world will bring big changes. Jesus will come back, and the dead will be brought to life. God will judge people, and only those who believe in him will be saved. The saved people will live forever in a new and happy world called the "paradise earth."